Let-off for looms



Feb. 14, 1928.' 1,659,236

w. P. sopla y LET-OFF- FOR LOOMS A Filed March 8. 1927 3 Sheets-Sheetl SZ 77 [i $53 Ef-t.. e

Feb. 14, 1928. "1,659,236

w. P. BoDlE LET-OFF Foa Lo'oMs Filed March e. 1927 s sheets-sheet 2 iff" y .ull

Miaadi@ Patented Feb. 14, 1928.

UNITED f STATES WILLIAM 1P. BODIE, OF GOLDVILLE, SOUTH CAROLINA.

Application led March 8, 1927. Serial No. 173,715.

This invention relates to let-olf mechanisms for looms and particularly to means for keeping as far as possible a uniform tension on the warp threads or yarn.

One of the objects of the present invention is to prevent the warp from becoming either too tight or too loose as a warp that'cannot be regulated causes breakage of the warp yarns and also causes breakage of shuttles,

l0 pickers and reeds. l

Another object is to provide means for keeping a constant tension on the warp which will prevent the warp from being slack on one end of the beam and tight on the other end of the beam.

Still another object is to preventundue tightening of silk warp where silk 1s being used with cotton as a warp. This is necessary because if the tension on the silk warp is too great then when the Vcloth is completed the cotton yarn will stretch and the silk will not and the goods so woven are not first-class.

A further object is to provide a warp tensioning mechanism which is particularly applicable to cases where manufacturers are required to run two or more warps or warps of two or more different kinds of yarn or thread to the loom at the same time.

Stil'l another object is to provide means whereby the yarn may be slackened to compensate for the stroke of the loom harness.

A still further object is to provide means whereby when the warp threads are placed under too great tension the beam on which the warp threads are wound may be positively rotated to relieve this tension, draft on the warp threads ordinarily acting to rotate the beam against a friction means 4U `which prevents overrunning of the beam.

' @ther objects will appear inthe course of the following description. j

My invention is illustrated in the accompanying drawings wherein Figure 1 is a side elevation of a iet-off' Fig. 4 is a section on the line 4-4 of Figure 2;

Fig. 5 is a section on the line 5-5 of Figure 1.

Referring to these drawings'lO designates the two uprights which constitute the sup-k porting frame for the rotatable beam 11. These uprights may be made in any suitable manner in' conjunction with the loom. The uprights are shown as being joined by a transverse bar or brace 12 and as having bearings 13'for the beam 11.' The beam 11 carries at one end the ratchet wheel 14 which rotates with the beam and mounted for rotation therewith `and With the bea-m is a friction disk l5 which has a slightly concave or recessed face.

Mounted upon one end of the upright 10 y and projecting out beneath the ratchet wheel 14 and friction wheel 15 is a support 16 upon which is mounted the tension lever 17. This is pivoted in any suitable manner upon the bracket or support 16 and extends out unequally beyond its pivot, it being shown as being so pivoted as to provide a relatively shortl arm'18 and a longer arm 19. The short arm is provided: with a plurality of holes arranged in longitudinal series and the longer arm is provided with a plurality of holes.

Extending over the friction wheel 15, shown as extending entirely around the friction Wheel, is a chain or other exible friction elementdesignated 20. One end of this is operatively connected to the short arm 18 by means of any suitable connecting device 2-1, and the other end is connected to the relatively long arm by' a suitable device of this character 22. The ends of the chain may be connected through any one of the perforations in the long or /short arm and thus the leverage exerted upon'this friction chain may be adjusted. j

Depending from the long arm 19 is a strap or equ1valent element 23 having a plurality of holes 24 and a coiled' contractile spring 25 which is mounted at its lwer end upon any suitablesupport by means of the eye 26 and may have its upper end connected in any one of the holes 24 and thus the tension of the spring upon the` long arm of the lever may be varied. Obviously if the spring be connected in one of the upper holes 24, the tension on the spring will be greater than if it be connected 1n one of the lower holes. It will thus be seen that the amount of fric-` tional resistance oEered by the friction element 2O tothe rotation of the disk l5 may be varied by changing the point of attachment of the ends of the friction element 20 and the ends of the lever 17 or by changing the point of engagement of the spring with the member 23.

Mounted upon a U-shaped supporting member 34 toV be hereafter described is a vertically extending arm 28. This arm at its upper end is formed to provide a head 29 which carries a pawl 3() pivoted at 31, the

.upper end of this pawl being urged outward by means of a spring 32 bearing against the shoulder1 33 formed on the head. The pawl is thus yieldingly projected and when this arm 28 is shifted toward the ratchet wheel 14 and reciprocated, the pawl will engage the teeth of the ratchet wheel and cause the ratchet wheel to travel in a counterclockwise direction which will unwind the warp from the beam 11. The arm 28 has a plurality of openings 27 for the passage of a bolt by which a U-shaped supporting member 341s attached thereto, which in turn is pivotally connected to a lever 35 pivotally mounted at one end, as at 36, and carryinglat its other end a rounded. lug 37 or other contact member with which a cam 38 engages at all times. This cam is mounted upon a shaft 39, the shaft being driven from any suitable portion of the loom not shown and being constantly driven when the loom is in operation. To this end it may be driven by a sprocket chain, belting or (rearing. The free end of the lever 35 is urged1 upward by means of a spring 40. It will thus be seen that the lever 35 and the arm or rod' 28 are continuously oseillated. A spring 4l is connected to the arm 28 and urges this arm toward the ratchet wheel 14.

For the purpose of preventing the pawl carried by the arm from engaging this ratchet wheel except when the tension on the warp is too great, I provide the following mechanism 4 Mounted upon the uprights 10 are the forwardly projecting brackets 42. These brackets are preferably slotted, as at- 43, and bolts 44 pass through these brackets and-through the uprights 10 so that the brackets may be adjusted. The extremities of the brackets carry eyes or bearings within which is disposed a. transversely extending rock shaft- 45. One extremity of this rock shaft which projects beyond the brackets carries upon it an arm 46 which is provided with a longitudinally adjustable weight 47 having a set screw 48 so that the weight may be shifted nearer to or further from the shaft 45. This arm 46 is Iadjustably mounted upon the shaft 45 by means of a set screw 49. The opposite end of the shaft beyond the corresponding bracket 42 has mounted thereon an approximately U-shapcd yoke 50 which embraces the rod 28 and the ends of this U-shaped member 50 are joined by a trans verse bolt 51 carrying a roller 52. T he member 50 is adjustably mounted upon the shaft by means of a set screw 53i An arm 54 is also adjustably mounted upon this end of the shaft 45, the extremity of the arm carrying a stop pin 55 which is adapted to strike against the adjacent bracket 42 and limit the clockwise rotation or oscillation of the shaft 45. This stop arm 54 is held in adjusted position upon the shaft by means of the set screw 56 and the arm is so adjusted upon the shaft with relation to the yoke 50 that the stop will strike the upper edge face of the bracket 42 when the roller 52 strikes against the face of the rod: 28. lVith this construction, when the shaft 45 is oscillated against the action of the weight 47, and the yoke 50 is turned towards a horizontal position, it will permit the rod 28 `to move toward the ratchet wheel 14 under the action of the spring 41. lVhen, however, the weight 47, due to the slackening of tension on the yarn, exerts its force to rotate the shaft45 in a counterclockwise direction, the roller 52 will act to withdraw the arm. The stop 55l so limits the movement of the yoke 50 that the yoke cannot bind upon the vertically rericprocating rod 28 and prevent or impede its reciprocation under the action of the cam 38.4

Adjustably mounted upon the shaft 45 to oscillate therewith are the outwardly projecting arms 57. These arms are held in adjusted position by means of set screws 58. lThe extremties of the arms carry projecting from them the angularly .projecting pins 59. Slidingly mounted upon these pms are the ends of a cross bar 60, this cross bar being rounded for the free passage of the warp threads. The eyes 6l in the eX- tremities of the cross bar are of sufficient sizeto permit a perfectly free movement of the cross bar upon the pins 59 and particu larly to permit a movement of one end of the 'cross bar inward of these pins independently of 'the other end of the cross bar.

Surrounding thepins 59 are the coiled compression springs 62. The lower endsof these springs rest against collars 63 which are adjustably mounted upon the pms 59 by means of set screws `64 and thus the tension on these springs 62 may be adjusted. The cross bar 60 is prevented from being forced olf the pins by means of stops 65 of any suitable character.

The yarn passes from the beam 11 over the 4rock shaft 45 and over the cross bar 60 and thence into the loom to form the shed therein in the usual manner. The arms 57 arev oov llU

not only rotatably adjustable upon the shaft but are longitudinally adjustable 'upon this shaft so that cross bars of various lengths may be used depending upon the width of the cloth being` woven. The operation of the mechanism is as follows: A constant tension is kept upon the beam 11, resisting the drawing 0E of the warp therefrom, by the friction mechanism conslsting of the chain 20, the disk l5, and the lever 17. As before remarked, this friction may be varied depending upon the number of counts or ends being used, upon the character' of the yarn or thread and the character of the goods being woven.

The yarn passes over the cross bar 60 which because of the weight 47, acts to keep a constant tension upon the warp threadsiindependent of the tension exerted by the friction mechanism. This tension is normally sufficient to keep the cross bar slightly depressedagainst the action of the weight 47 and as soon as there is any slackening of the tension the cross'bar 60 moves upward, thus increasing the tension on the threads. The shock t0 the threads given by the harness when the harness makes its stroke is taken up by the resilience of the springs 62, which will yield to these slight but sudden pulls upon the thread or yarn, thus preventing any tendency of the threads or yarn to break. If the tension becomes too great, so great that the friction device. will not ipermit the rotation of the beam oi' the strain upon the warp threads would beso great as to make silk threads, for instance, too tight or tend to break any of the warp threads, this action will depress lthe cross bar -60 against the action of weight 47 and swing this cross bar downward and forward, which will elevate the yoke 50. The spring 41 under these circumstances will draw the lrod 28 toward the ratchet wheel and this constantly reciprocated rod will engage with the ratchetl teeth and give one, two or more steps of rotation to the shaft or beam 1l sufficient to release the tension on the beam and threads. Thus it will be seen that I have provided means for positively rotating the warp beam to let olf the warp whenever the friction becomes too tight whereas in all other mechanisms known to me it is necessary that the attendant should constantly watch the tension of the threads and if they become too tight relieve the frictional engagement resisting rotation of the beam.

It will thus be seen that I have provided for compensating for slight variations in tension" by reason of the weight 47 on the arm 46 and cross bar 60, that I have provided for sudden pulls on the warp threads flue to the shock transmitted to the threads by the harness on making its stroke, and that l have provided for very delicate adjustrncnts of vthe frictional resistance exerted will be obvious that the farther out the ends of the chain are disposed in en agement with the lever 17, the greater will e the friction exerted by this chain, and the greater the tension on the spring 25, the greater will be the tension on the friction disk or drum.

'Where a 4warp gets -too tifht or too loose the shuttle is compelled to ride over the yarn or silk threads or make undershots or overshots to get through the shed. With my construction this is ing of shuttles, plckers, reeds, and the yarn itself. If the warp is once set to the proper tension on my mechanism it will continue at the same tension in the shed until the warp is entirely run off. Thevmechanism 1s re1- atively simple, may be readily applied in connection with all looms, and applied to the ordinary warp beam supports and experience has shown that there is very little wear or breakage `incidental to its use.

I claim e revented as is the break- 1. In a let-off mechanism, a rotatable warp beam, a rock shaft mounted below and parallel to the beam, radial arms mounted upon the rock shaft for adjustment rotatively thereon and having angularly projecting pins at their extremities, a transversely extending bar slidingly mounted upon said pins, said bar' being Iindependently movable uponr said pins at each c nd, springs urging said bar outward on the pms, the bar being adapted to support and tension the warp threads passing from said beam, and yielding means acting to rotate the rock shaft in a .direction to raise said arms, said means including an arm mounted upon the rock shaft for adjustment therearound, anda weight slidably mounted'upon said arm.

2. In a let-off mechanism for looms, a rotatable warp beam, a rock shaft mounted below, rearward of and parallel tothe beam, a forwardly projecting armon the rock shaft carrying a weight, downwardly and rearwardly projecting arms carried on the -rock shaft, a transversely extending bar mounted upon the arms and over which the warp threads pass, a constantly operated lol) power transmitting member, means for shifting said member toward the beam and into operative engagement therewith, and a yoke carried by the rock shaft and oscillating therewith, said yoke embracingsaid member and normally holding it'out of engagement with the beam but permitting the member to move toward the beam upon a depression of said bar due to `excessive tension on the warp threads.

3. In a let-off mechanism for looms, a rotatable warp beam, a rock shaft mounted below, rearward of and parallel to the beam, a forwardly projecting arm on the rock shaft carrying a weight, downwardly and rearwardly projecting arms carried on the rock shaft, a transversely extending bar mounted upon the arms and over which the warp threads pass, a constantly operated power transmitting member, means for shifting said member toward the beam and into operative engagement therewith, and a yoke carried by the rock shaft and oscillating therewith, said yoke embracing said member and normally holdin-g it out of engagement with the beam but permitting the member to move toward the beam upon a depression of said bar due to excessive tension on the 'warp threads, and a stop limiting the upward movement of the beam and the arm supporting the same.

4. A let-off mechanism for looms including a rotatable beam having a ratchet wheel, friction means resisting rotation of the beam, a constantly reciprocatable rod extending upward and rearward of the ratchet wheel and having a pawl engageable therewith, the rod being mounted to move toward or from the beam, means urging the rod in a direction to carry its pawl into engagement with the ratchet wheel, a rock shaft mounted rearward of but below and parallel to the warp beam, arms extending radiall downward and rearward from the roc shaft, a transverse bar operatively supported upon said arms and over which the warp threads pass, means yieldingly urging the rock shaft in a direction to carry said bar upward and rearward, a yoke mounted upon the rock shaft and embracing said rod said yoke normally extending downward and forward and thereby holding the rod away from, the ratchet wheel, and a stop limiting the rotation of the rock shaft under the action of said urging means, excessive tension on the warp threads acting to depress the'transverse bar and shift the rock shaft and yoke to a position permitting the engagement of the reciprocating rod with said ratchet wheel.

5. In a let-oft' mechanism for looms, a rotatable warp beam from which the warp threads pass, a movable warp thread teny sioning element disposed in front of and on a level below the beam and yieldingly urged in'a direction to tension the warp threads, said element beine' shiftable in a reverse di- 1 rection by an undjue tightening of the warp threads, a constantly operated power transmission member, means independent of the thread tensioning element urging the transmission member into4 operative engagement with the beam to rotate it in a directionto unwind the warp threads therefrom, and means connected to and operated by the tensioningelement and acting normally to hold the transmission mechanism out of engagement with the beam but permitting the transmission member to move towardthe beam upon a tightening of the warp threadsl and a consequent movement of the tensioning member.

V6. In a let-off mechanism for looms, uprights, a warp beam rotatably mounted upon said uprights over which the warp threads are wound and from which the warp threads pass downward and forward, a movable warp thread tensioning element disposed adjacent the beam and over which the warp threads pass and yieldingly urged in one direction to tension the warp threads, said element being shiftable in a reverse direction by undue tightening of the warp threads, a vertically extending, constantly operated power' transmission member yieldingly urged into operative engagement with the beam to rotate it in a direction to unwind the warp threads, and means connected to and operated by theh tensioning element and normally acting to hold the transmission member out of engagement with the beam but permitting the tensioning member to move into engagement with the beam upon a depression of the tensioning member due to excessive tension on the warp threads.

7. In a let-off mechanism for looms, a rotatable warp beam having a ratchet wheel `threads adjacent the beam and over which the warp threads pass, said element being yieldinglyurged upward in a direction to tension the warp threads but being shiftable in a reverse direction by undue tightening of the warp threads, a constantly operated, vertically reciprocating power transmission member yieldingly urged into operative position relative to said ratchet wheel to rotate the beam ina direction to unwind the warp threads, anda yoke operated by and shiftable with the tensioning element, through which yoke the transmission member passes, said yoke acting to hold the transmission member out of engagement with the beam when the tensioning member is in normal position but permitting the transmission member to operatively engage with `the ratchet wheel on the beam Aupon a depression f the tensioning member due to excessive tension on the warp threads.

8. In a let-off mechanism for looms, a rotatable warp beam from whichwarp threads pass, the beam having a ratchet wheel upon one end, a pivoted warp thread tensioning element disposed in front of and on a level below the beam and yieldingly urged by a weight in a direction to tension the warp threads. said element being shiftable in a reverse direction against the action of the weight by an undue tightening of the warp threads, a constantly reciprocated power transmission member having a pawl engageablelwith the ratchet' wheel, means independent of the thread tensioning element urging the transmission member into operative engagement with the ratchet 'wheel on the beam to rotate it in a direction to unwind the warp threads therefrom, and means carried by the tensioning element yieldingly holding the transmission mechanism out of engagementI with the beam but permitting the transmission member to move toward the beam under the action of 'its urging 10 means upon a tightening of the warp threads.

In testimony whereof I hereunto aiiix my signature.

WILLIAM P. BODIE. 

